The objective of this proposal is to develop and market sensitive and highly specific assays for the detection of cancers based on the expression of the immortalizing enzyme telomerase. Using a proprietary PCR-based assay for telomerase activity designated TRAP (Telomeric Repeat Amplification Protocol) immortal cells can be detected in clinical specimens. Furthermore, because cell immortality is an inherent feature of the malignant phenotype, it is likely that telomerase expression will serve as a prognostic indicator. Having demonstrated the utility of the TRAP Assay in cancer cell lines, a quantitative version of the assay will be developed. In addition, we will use the recently cloned RNA component of human telomerase as a molecular probe for the development of an in situ RT-PCR assay that will allow the identification of telomerase positive cells in pathologic sections. These assays will be evaluated in a pilot trial in breast cancer comparing telomerase expression with other prognostic indicators and will determine whether telomerase expression can be used to predict clinical outcome. Success of these studies would support the hypothesis that telomerase is both a marker and prognostic factor in breast cancer; an observation that is likely to be true in other cancers. PROPOSED COMMERCIAL APPLICATION: If successful in Phase I, two novel, sensitive, highly-specific, and quantitative diagnostic assays for the detection and progression of cancer based on the expression of the immortalizing enzyme telomerase will have been developed and validated. A pilot Phase I and the proposed Phase II studies will enable us to assess the potential for the use of telomerase as a prognostic indicator in breast cancer by comparing telomerase expression with that of a number of recognized prognostic indicators as well as clinical outcome. If successful, the assays will be evaluated in other cancers, appropriate regulatory approval will be obtained, and the technologies commercialized.